Heat exchanger finned tube



Jan. 9, 1951 1T.L'Eh\Y HEAT EXCHANGER FINNED TUBE Filed Dec. 2, 1946 INVENTOR THOMAS J. BAY

ATTORNEYS Patented Jan. 9, 1951 UNITED STATES PATENT OFFlCE 2,537,024 near EXCHANGER mm TUBE Thomas J. Bay, United States Navy Application December 2, 1946, Serial No. 713,451

Claims- (Cl. 257-2622) (Granted under the act of March 3, 1883, as amended April 30, 1928: 370 0. G. 757) Finned tubes, .according to the present invention, may be used in double tube type heat exchangers and tubular heat exchangers including surface condensers for steam and refrigerants. Improved heat'exchangers of my design are particularly suitable for use in Diesel and steam driven naval vessels.

,The'use of fins attached to theoutside surface oi a tube increases the effective heat transfer surever, in heat exchangers and condensers present the difiiculty of securing theends of the tubesyin" tube sheets .dividing the two. mediums to be treated.

The .addition of fins to a tube increases the overall diameter of the tube. As a result. the hole in the tube sheet through which the tube must pass in order to be installed in the heat exchanger is too large to permit the tube to be secured by conventional methods. The present invention provides for overcoming this difiiculty by expanding and belling the ends of the finned tube into a metallic bushing with an outside diameter slightly greater than the overall diameter of the .tube with fins. the tube sheet by packing, soldering or silver brazing.

The invention also resides in certain novel features of component structure and arrangements which facilitate the carrying out of the foregoing objects and which contribute both tothe simplic ity of the device and to the reliability of operation as well as to the ease andfexpeditious manner of construction.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings in which:

Fig. 1 is a longitudinal partial cross section showing a double tube construction.

Finned tubes, how-;

to improvements in heat ble tube type heat exchanger.

.i'ace, of the tubewhich improves the heat trans- 3 v fer rate'through the tube.

by. an escutcheon pin I6. belled andexpanded into bushing I3 which has Fig. 2 is a longitudinal partial cross section showing-a single tube construction.

Fig. 3 is a longitudinal partial cross section showing an alternative arrangement for securing the tube insingle tube construction.

Fig. 4 is a longitudinalpartial cross section 01 another single-tube construction.

Whilethe' invention is susceptible of various modifications. and alternative arrangements, I have shown in the drawings andwill herein (18- scribe i'ndetail the preferred embodiments- It is to be understoodjhowever; that 'Ido not intend to limit the invention by'such disclosure for I aim to cover all modifications and alternative arrangements falling-within the spirit and scope of the invention as defined in' the appended claims. I

Fig. 1 shows the tube II carrying an extended spiral wire fin l2 which is secured by bushing l3 of constant diameter in a tube sheet Id of a dou- The fins I2 are formed by a small diameter spiral wrapped coil of suitable wire through which a bindihgwire l5 has been threaded. The binding wire is wound several times around the tube II beyond the end loop of the coil and is secured to the bushing I3 an outside diameter slightly greater than the overall diameter of the tube with fins.

To insure positive contact between the coil I2 forming the fins and the tube H, the finned tube assembly is tinned. The bushing I 3 is secured in the tube sheet I4 by packing II. The double tube arrangement is provided by a surrounding tube it which is expanded into the second tube sheet I9.

A-similar arrangement may be provided at the This bushing is secured in other end of tubes II and I 8. The tube 18 is of slightly larger diameter than the coiled helical wire I2 so as to confine any liquid flowing be- .tween the two tubes I I and I8 to close proximity The fluid to be cooled fiows through tube ll, and the cooling fluid flows to the coil I2.

through tube I8 and the aperture between plates I9 and I4 in a manner well known in the art.

--In Fig. 2 a tubular type heat exchanger Without the outside tube is shown. The finned tube II with spiral coil I2-and binding wire I5 is se= cured as in Fig. l by bushing I3 and packing Ill in tube sheet I4.

In Fig. 3 an alternative method of securing a finned tube in a tube assembly sheet is shown. The bushing I3 is secured directly to the-tube sheet I4 by soldering, silver brazing or welding. It may also be threaded if desired.

The end of tube Ii is In Fig. 4 is shown an alternative arrangement for securing one end of a finned tube A, the

other end being supported by one of the arrangements described above for finned tube II. The belied end 20 of tube HA fits a complementary opening in tube sheet 2|. Fin tubes of type I IA are installed in a heat exchanger or condenser by inserting the bushed ends through a tube sheet such as H which has been drilled for the bushed end finned tubes. The end of the fin tube A not having a bushing is expanded and belled into the tube sheet 2 I.

In the case of tubes packed at both ends, the

may be so constructedas to provide threads or serrations in the stufling box or hole in the tube sheet I4 and in the metallic bushing l3 so that the packing 11 between these parts will be restrained thereby preventing any axial movement of the finned tube due to expansion.

The tubes may have the same type of support at both ends o various combinations or the supports shown may be used.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalty thereon or therefor.

I claim: 1

1. In a heat exchanger the combination of a tube, a hollow coil surrounding the tube, a binding element inside the coil, plate-supported bushings at each end of said tube, said element being fastened to said bushings.

2. A tube assembly adapted for use in a heat exchanger, said assembly comprising: a tube; a hollow coil surrounding said tube; bushings fixed to each end of said tube and adapted to be platesupported; and a binding element inside of said coil and fastened to said bushings.

3. A tube assembly for use in a heat exchanger, said assembly comprising in combination: a tube, a hollow coil surrounding said tube and fixed in extending inside of said coil.

4 outwardly from said tube to an extent not greater than the diameter of said bushing; and a binding element fastened to each of said bushings and said tube to an extent not greater than the diameter of said bushing; and a binding element fastened to each of said bushings and extending inside of said coil.

5. Ina heat exchanger, in combination: a tube;

' ing recess in the outer face of said sheet posipositive contact therewith along the longitudinal extent thereof; a bushing adapted to be supported by a plate and fixed to each end of said tube; said coil being constructed and arranged to project tioned adjacent to and having-a diameter greater than-said aperture; a bushing fixed to one end of said tube and mounted in said aperture; a packing held in said recess and arranged to seal said bushing in said aperture; and abinding element fastened to said bushing and extending inside said coil; said coil being constructed and ar-, ranged to project outwardly from said tube to an extent not greater than the diameter of said bushing.

THOMAS J BAY.

REFERENCES CITED The following references are of record in. the file of this patent:

UNITED STATES PATENTS Number Name Date 500,733 Ashley July 4, 1893 997,872 Waller July 11, 1911 1,614,159 Smith Jan. 11, 1927 1,618,797 Bennett Feb. 22, 1927 1,716,743 Still June 11, 1929 1,856,618 Brown May 3, 1932 2,028,471 Parent et a1 Jan. 21, 1936 2,308,319 Stanton Jan. 12, 1943 r" 2,331,437

' Sterick .1 Oct. 12, 1943 

